Synthesis of PolyDADMACs
The synthesis of low to medium molecular weight cationic polyelectrolytes through cyclopolymerization of diallyldialkylammonium halides, particularly diallyldimethylammonium chloride (DADMAC) is well known in the art, and these polymers have been used extensively as coagulants in many practical applications. Although a linear polymeric structure is normally prepared, various multi-functional vinyl monomers and synthetic procedures can be employed which lead to the branching or crosslinking of the polymer. Polymers which are branched maintain a discrete molecular identity with smaller polymeric segments emanating from the main polymeric chain. Crosslinked polymers have a connection between discrete polymer chains to form a network-type structure.
The following patents disclose various syntheses and applications of polyDADMACS:
Japanese Patent No. 90041528 discloses a method for the synthesis of water insoluble crosslinked polyDADMACs, useful as ion exchange resins. The crosslinked polyDADMACs are copolymers of 74/26 DADMAC/TAPD and 67/36 DADMAC/N,N'-dimethyl-N,N,N'N'-tetraallyl-2-butene-1,4-diammonium dichloride.
French Patent No. 1,494,438 discloses a composition and method of synthesizing a water soluble, highly crosslinked diallylammonium chloride composition, typically a water soluble, highly crosslinked polyDADMAC. The crosslinking agents used in this patent are triallylamine hydrochloride, methylene bisacrylamide and tetraallylammonium chloride. The composition is synthesized in solution form and is useful for electron conductive paper coating applications.
U.S. Pat. No. 4,100,079 discloses that copolymers of DADMAC and a monomer capable of post-crosslinking polymerization are useful as acid thickeners in oil well drilling and fracturing operations because of their acid, heat, and salt stability.
U.S. Pat. No. 4,225,445 discloses that branched emulsion or suspension polymers of DADMAC are useful for acid thickening in oil well drilling and fracturing fluids.
U.S. Pat. No. 3,968,037 discloses that highly crosslinked cationic polyelectrolytes as highly effective flocculants for dewatering of activated sewage may be produced by the inverse emulsion polymerization of water soluble cationic monomers, including DADMAC, in the presence of a polyolefinic unsaturated comonomer. The highly branched cationic polyelectrolytes synthesized in the inverse emulsion form have better water solubility than those synthesized in solution, suspension or bulk polymerizations.
European Patent No. 0 374 458 discloses a composition and method for making highly branched, water soluble polymers with high molecular weight, including highly branched polyDADMAC. The composition is useful as a flocculant. The method comprises polymerizing one or more water soluble monomers (including DADMAC) and a branching agent (methylene bisacrylamide) in the presence of a chain transfer agent (isopropanol). The composition is useful in flocculating dispersions of suspended solids, such as sewage sludge.
European Patent No. 0 264 710 B1 discloses a composition and method for synthesizing highly branched, water soluble polyDADMACs. The method comprises adding a mixture of a branching agent and DADMAC monomer to the reactor in the presence of a chain transfer agent (triethanolamine).
German Patent No. DD 292 641 A5 discloses that water soluble, highly branched polyDADMACs are useful as flocculants for the removal of solids from aqueous suspensions of sludge containing coal and for the dewatering of sludge from industrial waste water or sewage. The process can be used in the manufacturing of briquettes to obtain usable water and to recover coal. The water can be used directly and the separated solids can be used as fuel.
German Patent No. DD 292 218 A5 discloses that water soluble, highly branched polyDADMACs are useful in the dewatering of sludge from industrial waste water or sewage. The process can be used to remove suspended inorganic solids in processing water, in clarification of municipal or industrial water, and in technical separation processes.
German Patent No. DD 292 219 A5 discloses the preparation of a highly branched polyDADMAC, which is subsequently heated and stirred to remove water to obtain a powder with an active substance content of 70%.
German Patent No. DE 3733587 A1 discloses that water soluble, highly branched polyDADMACs are useful in retention and drainage in paper manufacturing.
German Patent No. DD 293 500 A5 discloses that highly branched polyDADMACs are effective in the removal of suspended solids from waste water and waters containing 10-4-10 g solids/L.
German Patent No. DD 292 642 A5 discloses that solids are separated from aqueous suspensions or slurries by the addition of a water insoluble acryloguanamine copolymer, and a water soluble, highly branched polyDADMAC. The process is useful in processing drinking water, in the production of usable water, and in the purification of municipal and industrial waste waters.
Soviet Union Patent No. SU 1595851 A1 discloses a method for preparing methylene bisacrylamide-crosslinked polyDADMAC in emulsion or in alcohol. The resulting polymer is useful as a sorbent.
German Patent No. DD 261 800 A1 discloses that water soluble, highly crosslinked polyDADMACs are useful as reversible bonding packaging materials such as paperboards.
U.S. Pat. No. 5,393,381 discloses that the use of branched polyacrylamide and bentonite together has a synergistic effect on the retention of the bentonite in the sheet to yield paper having improved quality, opacity and smoothness, reduced porosity, improved absorbency, improved running on the machine, better production economy, and lower concentration of residual bentonite in the backwater, thus reducing problems of disposal. The branched polyacrylamide is preferably a cationic copolymer of acrylamide and a cationic ethylenically unsaturated monomer chosen from quaternized or salified dimethylaminoethyl acrylate, acrylamidopropyltrimethylammonium chloride, DADMAC and dimethylaminoethyl methacrylate.
U.S. Pat. No. 5,387,318 discloses that polyacrylamide grafted with cationic polymers, optionally with a branching agent, are useful for laser print deinking loop clarification.